Resum:

Quantum dots (QDs) are structures that show quantum confinement in all three directions of space. In particular semiconductor QDs are nanometric structures and they have great potential in the development of optoelectronic devices [1]. In particular, the optoelectronic devices that exploit the quantum properties of a single nanostructure [2] are of great interest in the field of cryptography and quantum information technologies [3] for their capability to generate non classical light states, such as single photon emission and entangled photon pair generation [4,5] and in the fundamental studies of cavity quantum electrodynamics (cQED) in solid state [6]. The development of this kind of devices exploits in many cases the light-matter coupling that takes place when an emitter is located in a high quality factor optical cavity. For the development of single photon sources, an increment of the emission rate is obtained due to Purcell effect [7]. Nevertheless, the fabrication of single QD-photonic mode coupled systems is nowadays a technological challenge; it is necessary to simultaneously achieve the spectral and spatial matching of the emission of the nanostructure and the photonic mode: the nanostructure emission wavelength should match the spectral position of the fundamental mode of the optical cavity and the nanostructure should be located at the highest electric field intensity of the photonic mode. Among other semiconductor systems, InAs/GaAs has been widely studied because of the high quality InAs quantum dots obtained by epitaxial Stranski-Krastanov selfassembly in GaAs(001) surface [8]. These self-assembled quantum dots (SAQDs) show high structural and optical quality s but they present an important practical drawback as it is not possible to know their nucleation site a priori. Due to the strict requirements for the fabrication of single nanostructure based devices, the development of fabrication processes to obtain site-controlled quantum dot (SCQDs) is mandatory. Establishing scalable fabrication processes of this kind of devices require to a priori define the spatial location of the active nanostructures. 224 Epitaxial growth on nanohole-patterned substrates has been established as the main technological approach to fabricate SCQDs [9,10]. Nanoholes patterned in the substrate surface can act as preferential nucleation sites for QD formation due to the surface chemical potential minima located at the bottom of these nanoholes, which in addition to the incorporation kinetics determines the SCQDs formation. Nevertheless, growth on patterned substrates imposes important limitations compared to the growth of QDs by means of self assembly processes. First, high resolution lithographic techniques are used for the fabrication of the patterned substrates and defects or contamination could be introduced in the substrate surface. Second, standard procedures in epitaxial growth, such as surface oxide thermal desorption and the growth of thick buffer layers, are not suitable for patterned substrates due to the need to preserve the patterned motifs. These limitations result in that the nanostructures are grown in proximity to the regrowth interface, which may degrade the optical properties of the obtained nanostructures [11]. Therefore, it is crucial to study and optimize all processes involved in the fabrication of SCQDs to obtain nanostructures with suitable properties for its practical application in devices. In addition, as many applications require the formation of a single QD at given positions in a reproducible process, it is mandatory to optimize the occupation statistics (number of QDs obtained per pattern motif) in the patterned motifs